The research described in this application, both in terms of career goals and a dissertation research project, is designed to examine genetic and environmental mechanisms that may shed light on how parental depressive symptoms compromise the early development of emotion regulation in children. The pathways by which the relations between parental depression and child emotion regulation emerge are not understood, in part because most of the research cannot disentangle genetics and environment in studies of only biologically related dyads. My career goal is to develop the skill to study gene-environment interplay as it relates to the intergenerational transmission of mental health problems. Although heritability research indicates the greater risk of affective disorder among biological offspring of depressed parents, it also demonstrates that genetic contributions only explain a portion of the variance. It is essential to identify phenotypic indicators of disorders in early childhood through the disentanglement of genetic and environmental risk. To better prepare myself for conducting longitudinal research that addresses the gene-environment interplay in offspring of parents with depressive symptoms, I aim to further develop skills at conceptualizing and measuring emotion in social interaction, learn and apply strategies used to disentangle gene-environment interplay, and develop a working knowledge of molecular genetics as it applies to mental health disorders. The dissertation research is a first step toward my career goal. I will investigate the emotional nature of parent-toddler interactions with the aim of specifying the degree to which both genetic and environmental factors contribute to poorer emotion regulation in toddlers who were adopted as infants. It is expected that the emotional quality of the parent-child interaction will be predicted by both the genetic risk of the child and the environmental risk. I will also test the hypothesis that the emotion regulation of genetically vulnerable children will be more influenced by the quality of the parent-child interaction than children without genetic risk. Similarly, the emotion regulation of children who are living in an environment with a depressed parent will be compromised by negative qualities of the parent-child interaction. These questions will be examined in a prospective adoption study of 361 adoptive children, their biological parents, and their adoptive parents. Emotional qualities of adoptive parent-toddler interactions and toddler emotion regulation will be based on observational data. Parental depressive symptoms, in both biological and adoptive parents, will be studied over time. This research will identify specific sources of environmental risk, particularly for already vulnerable children, with the aim of defining crucial targets of intervention.